Basically cancer is a terminology which is used to describe several forms of malignant diseases. There are many forms of cancers that affect humans in various body parts. Cancer makes cells to grow uncontrollably in that; cells begin to divide beyond their expected sizes and as a result tissues surrounding malignant cells get destroyed. One of the main characteristic of cancer is metastasis where the cancer spreads to various parts of body. Malignant cancers are different from benign tumors which lacks the property of spreading to other areas. Many types of cancer results in tumor while a few types are like leukemia. Oncology is a medical study which deals with prevention, diagnosis as well as treatment of cancer. Cancer is a disease which does not discriminate because it affects people of all types though its prevalence is high among the aged (Ko, Dollinger and Rosenbaum, 2008).
Prevalence of cancer
Statistics that were carried out in 2007 indicated that 13% of all deaths are as a result of cancer. This is approximately 7.6 billion across the world that succumb to cancer. Cancer results from genetic abnormalities in cells that have been transformed. Abnormalities in the genetic materials occurs as a result of a number of factors for instance due to carcinogens like tobacco smoke, infectious agents as well as radiation or other known or unknown dangerous chemical substances. Other cancers may result because of genetic abnormalities that may occur during DNA replication and such errors are inherited therefore there are people who genetically develop cancer because the cancer cells were passed to them from the previous generation. The ability for one to inherit cancer is generally steered by the complex interactions that usually occur between a person’s genome and the carcinogens. Genetic errors present in cancer affect two types of genes.
Agents that promote cancer activate cancer cells making them to develop new properties like hyperactive division and growth. These agents also shield the cancer cells from the normal cell death that occurs to all abnormal cells. Cancer cells bypass the normal boundaries of cells damaging other tissues that surround them, the agents that cause cancer gives cells the ability to establish and survive in new environments. All cells have tumor suppressor genes but cancer cells loose this ability and as result they become ineffective as cells. Basically cancer cells are not in a position to accomplish some of its functions like DNA replication, adhesion and orientation that occurs within tissues as well as control of the cell cycle. Cancer cells are not in a position to interact with protective immune cells as expected. These are some of the modifications that occur in cells after being invaded by cancerous agents (Delfino and Day, 2006).
Diagnosis of cancer
Cancer diagnosis involves tissue examination (histologic) of biopsy. Some of the initial cancer signs are symptomatic whereby radiographic imaging of abnormal cells occurs. There are many factors that come into play in treating cancer. These factors include the type of cancer, where the cancer is at what stage the cancer has reached. Cancers which may not to be treated are other times forced into diminution. Diagnosis is the initial step before thinking of treating the specific cancer and a number of ways are employed in treating the disease. Cancer can be treated through a combination of radiotherapy, surgery as well as chemotherapy. Specific treatment of the various forms of cancer is improving as scientists venture into further research. For instance there has been a marked improvement in production of drugs which are useful for therapy and good at detecting abnormalities which are molecular. This is very useful because early detection is important in reducing the damages that are caused by the timorous agents (Gutman and Gutman, 2005).
Classification of cancer
The type of cancer that a patient has greatly influences the diagnosis of the disease. Other factors that influence prognosis of cancer are the size of the tumor as well as the developmental stage. Specific molecular markers and histologic grading are very important in diagnosis and selection of the appropriate treatment. Cancer is basically classified depending on the original tissue of the tumor as well as the cell type resembling it. For instance carcinoma is cancer that develops from the epithelial cells and its covers most common cancers like colon, prostrate, breast and lung cancer. Cancers that develop in the connective tissues are manly referred to as sarcoma. Malignant tumors which form in the blood or hematopoietic cells are simply referred to as leukemia or lymphoma (Szyf, 2005).
Tumors that develop in the germinal cells or totipotent cells; testicles as well as ovaries are referred to as germ cell tumor. Some cancers usually take the form of embryonic or immature tissues. Such malignant tumors are referred to as blastoma or blastic tumors. Generally the naming of malignant tumors uses terms like blastoma, carcinoma as well as sarcoma on the basis of the origin of the tumor. For example liver cancer is named hepatocarcinoma, while cancer that affects fat cells is referred to as liposarcoma. Common cancers are named using the English name of that region for instance breast cancer. It’s important to note that benign tumors are not cancerous and they are simply named using the suffix –oma, in this case the root of the tumor is the name of the organ. For example benign tumor of the uterus is referred to as leiomyoma (WHO, 2002).
The symptoms and signs of cancer
The symptoms of cancer are grouped into three categories. The first category of is termed as local; these may include unusual swelling or lumps. Other local symptoms may include ulceration, hemorrhage and pain. Other times the skin surrounding the cancer may become yellow due to compression. The second category is metastasis symptoms which include abnormally large lymph nodes, enlarged liver, cough, bone pain and hemoptysis among others. One of the common features of advanced cancer is pain though it’s not usually among the first symptoms. The final category is symptoms that are considered to be systemic. These symptoms include fatigue, weight loss, wasting, poor appetite, anemia, night sweats that are usually excessive among other many complications. Some conditions that may not be absent in advanced cancer is hormonal changes. It’s important to understand that the above symptoms may not be directly related to cancer because they can be as a result of some other medical complications or conditions (Falvo, 2005).
The causes of cancer
Cancer is a term that defines a wide range of diseases therefore the causes of all these diseases may be different depending on their biology. Cancer is not only limited to human beings because it can be acquired by other organisms for instance plants as well as animals. Almost all cancers result from errors that occur in cancer cells. Errors can occur in any replicating or dividing cells and for these reason it’s important that proper correction of the particular errors occurs in order to avoid abnormal growths. Many errors that occur in germinal cells are usually passed on to the next generation. Naturally the body has a number of methods or strategies which it employs in fighting cancerous cells. Some of these methods include apoptosis where the cancerous cell is destroyed or killed, by employing helper cells as well as senescence.
The methods that are employed by the body to destroy the cancerous cells often fail and in this case the cancerous cells grow to a cancer. This occurs if the place where that particular cell is located has the ability to make the abnormal cell to grow and divide. Good examples of environments that promote growth of cancerous cells include environments with carcinogenic substances, environments with hypoxia or places that experience frequent damage and heat. Cancer develops progressively therefore accumulation of the cell errors slowly grows to cancer. The cell becomes cancerous when it starts to act abnormally or in the opposite way. Most of the time cancers causing errors are self amplifying; they have the ability to grow at an exponential rate. Some of the factors that contribute to faster accumulation of errors in cells include mutation (Morris and Kearsley, 1998).